In order to make full use of the purification function of wetland, with an urban wetland park used as an example, a two-dimensional hydrodynamic model was constructed, and a water age calculation module was introduced. With the grid size ranged from 3 m to 5m, the lake area was finely generalized, and the hydrodynamic status and water exchange characteristics of the lake area were calculated and analyzed with the model. Comprehensive comparison of calculation results of different engineering schemes shows that the fluidity and spatial distribution of hydrodynamic condition are relatively better in the lake area in scheme 2 and scheme 3, and there are stagnant water areas only in the central lake area and the central part of the third multi-pond purification area. To further improve local hydrodynamic conditions, it is suggested that the push flow aeration equipment should be arranged in relatively stagnant water areas to improve the fluidity and water exchange capacity. With the model, specific scheduling schemes can be formulated in combination with other factors, so as to provide decision support for the river and lake system connection and ecological water supply.